The first line of code in a project does not need to be clever. It needs to be a line that runs. The reliable way to start any project is to get the smallest possible program working from start to finish (it prints one line, serves one page, or reads one file), commit it, and only then add the first real feature. This post shows that method, then lists the literal first lines you will see in common languages.<\/p>\n
The blank file asks you to make every decision at once: structure, names, libraries, error handling. You cannot make them well yet, because you have not learned anything about the problem. Writing code is how you learn what the problem is. So the goal of the first line is not to be right. It is to turn an empty file into something you can run, change and learn from. If the blank page itself is what stops you, our post on why you can’t start coding<\/a> goes into the psychology.<\/p>\n Write the smallest program that starts, does one visible thing and exits. For the word counter:<\/p>\n Run it. It prints The same idea in a web project is a page that says “hello” and loads in the browser. In a mobile app it is the default template running on an emulator. In a data project it is loading the file and printing its first five rows.<\/p>\n Take the example you wrote down and turn it into code before the feature exists. Put the logic in a function so it can be tested without files or user input:<\/p>\n Running this prints With a file If by “first line” you mean what a file usually begins with, this is what you will see. None of these is required for a program to work, so do not stall on them.<\/p>\nBefore you type: five minutes of preparation<\/h2>\n
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\"the cat sat\"<\/code> gives 3<\/code>.<\/li>\ngit init<\/code>.<\/strong> Being able to undo anything makes experimenting cheaper.<\/li>\nThe method: walking skeleton, then first test, then first feature<\/h2>\n
Step 1: make it run<\/h3>\n
def main():\n print(\"wordcount: starting\")\n\nif __name__ == \"__main__\":\n main()<\/code><\/pre>\nwordcount: starting<\/code>. That is a real result: your editor, your interpreter and your file are all set up correctly. A surprising number of beginner problems are really setup problems (wrong folder, wrong Python version, file saved under the wrong name), and this step finds them while the program is still ten lines long.<\/p>\nStep 2: write the first test<\/h3>\n
def count_words(text):\n return len(text.split())<\/code><\/pre>\nfrom wc2 import count_words # wc2.py is the file that holds count_words\n\nassert count_words(\"\") == 0\nassert count_words(\" the cat\\n\") == 2\nprint(\"ok\")<\/code><\/pre>\nok<\/code>. str.split()<\/code> with no argument splits on any run of whitespace and ignores leading and trailing whitespace, which is why the extra spaces and the newline do not produce phantom words. Writing the test first made you think about those edge cases before they became bugs. You do not need a test framework to start. Plain assert<\/code> lines are enough, and you can move to pytest or unittest when you have more than a handful.<\/p>\nStep 3: connect it to the real input<\/h3>\n
import sys\n\ndef count_words(text):\n return len(text.split())\n\ndef main():\n path = sys.argv[1]\n with open(path, encoding=\"utf-8\") as f:\n print(count_words(f.read()))\n\nif __name__ == \"__main__\":\n main()<\/code><\/pre>\nnotes.txt<\/code> containing two lines, “the cat” and “sat on the mat”, running python3 wc2.py notes.txt<\/code> prints 6<\/code>. The project now works end to end. Commit it. Everything after this is improvement: handle a missing file, add a flag for lines, read from standard input. Each is a small step on top of something that already runs.<\/p>\nThe literal first line in common languages<\/h2>\n